Conduction and origin of evoked potentials in the somesthetic pathway

Abstract

In 24 normal subjects, sensory conduction velocity increased progressively from the distal to the proximal segments of the peripheral nervous system.In the central somatosensory pathway, sensory impulses slowed down at a rate much greater than what could be expected from just the three known synaptic delays (1 ms each) in medulla, thalamus and somatosensory cortex.The present data point to the special characteristic of conduction in the thalamo-cortical axons as the main cause for the deceleration observed in the central somatosensory pathway.A conduction velocity of 14 m/s has been calculated for this last segment.However it is also possible that sensory conduction in the medial lemniscus might be reduced in relation to the conduction values in the peripheral segments.